Jim Dollard has an extensive background in codes and standards. If you have a query about the National Electrical Code (NEC), Jim will help you solve it. Questions can be sent to email@example.com. Answers are based on the 2017 NEC.
What does “dead front” mean? While pulling conductors in existing conduits for new branch circuits into an existing panelboard, the safety director on a large account approached us. He was concerned about the possibility of contact with energized parts with just the interior cover on. We explained that no live parts were exposed because the dead front was on and we were working safely. If a panelboard has the interior trim installed and the outer trim off, you cannot see the bus bar and terminations. Is the interior trim considered the dead front?
No, the dead front in your case consists of more than one part and must be completely installed for the panelboard to be considered “dead front.” A load center typically has a one-piece dead front while a panelboard in a commercial occupancy is typically an assembly with one part over the circuit breakers, bus and terminations and a second part that completes the dead front by covering the wiring spaces completely.
Per the Article 100 definition, electrical equipment is considered to be “dead front” when there are no live parts exposed to a person on the operating side of the equipment. In your case, there were exposed energized parts as you installed conductors. It is important to understand that—without the complete dead front installed over an energized panelboard—there are exposed live parts.
The NEC definition for “exposed (as applied to live parts)” means that a person is capable of inadvertently touching live parts or approaching nearer than a safe distance. People working in the space in front of the panelboard could inadvertently come into contact with live parts. NFPA 70E provides prescriptive requirements for electrically safe work practices, including justification thresholds for energized work and safe work practices where people are exposed to energized conductors or circuit parts.
GFCI inside a cabinet?
The text in 210.8 has me confused. We have always provided ground fault circuit interrupter (GFCI) protection for receptacles in cabinets below sinks. Does the door on the cabinet negate the need for GFCI protection? Receptacles below the sink are typically used for a fixed appliance but can be used in a commercial bar setting in a repair or maintenance situation. How about a long island in a dwelling unit with just one receptacle on the far end away from the receptacle installed under the sink? Homeowners may get creative and use the receptacle in the cabinet for countertop use.
The parent text in 210.8 was revised in the 2017 NEC revision cycle. It applies to all five first-level subdivisions in Section 210.8. GFCI protection is required for receptacles installed less than 6 feet from sinks. See list items 210.8(A)(7) for dwelling units and 210.8(B)(5) for other than dwelling units. The revised text provides prescriptive text that describes how to make the measurement. It is the shortest path the cord of an appliance connected to the receptacle would follow without piercing a floor, wall, ceiling or fixed barrier, or passing through a door, doorway or window. Where a sink is involved, measure from the top inside edge of the bowl of the sink.
It is typical to see a receptacle installed under or adjacent to a sink in a dwelling unit for appliances such as a garbage disposal. This means our measurement of the shortest path to the sink would be through an opening with a cabinet door. Therefore, GFCI protection is not required for the receptacle. However, if the appliance supplied by the receptacle is a dishwasher in a dwelling unit, first-level subdivision 210.8(D) would require GFCI protection. The existing requirements for receptacles on the kitchen countertop cover potential use of appliances. It would be unusual to see someone plug a portable appliance into an undercounter receptacle, but as you described, it is possible. Those performing maintenance or repair are required to be provided with GFCI protection by Section 590.6 and applicable OSHA regulations.
Meeting room receptacles
During the bid process for a renovation that is changing two floors of hotel rooms into meeting rooms, I had to inform the designer of new requirements in the NEC that mandate a given number of receptacles in meeting rooms. This is the first time I am using this requirement, and I am surprised the NEC permits it. This design issue should be left to the owner and the engineer. There also is a conflict within the requirement itself. Can the owner or designer choose wall receptacle placement, or do they have to be installed in strict compliance with 210.52(A)(1) through (A)(4)? Is a school room a meeting room?
New Section 210.71 requires a minimum number of receptacle outlets in meeting rooms that meet the prescriptive requirements of this section. Section 90.1 clearly states that the NEC is not intended as a design specification; its purpose is the practical safeguarding of people and property from hazards arising from the use of electricity. This new requirement recognizes serious hazards that are found in meeting rooms where participants bring electronic equipment, creating the need for extension cords running all over the meeting room.
This is not an example of the NEC stepping on the toes of a design engineer; it is simply mandating a minimum number of receptacles for safety-driven reasons. Section 210.71 applies only to meeting rooms that are 1,000 square feet or smaller. When determining the size of a room where there are movable partitions, the room size is determined based on the smallest size meeting room(s).
The informational notes (IN) that follow the parent text provide significant clarity. IN No. 1 explains that this requirement is intended to apply only to meeting rooms that are designed or intended for the gathering of seated occupants for such purposes as conferences, deliberations or similar purposes, where portable electronic equipment such as computers, projectors or similar equipment is likely to be used.
IN No. 2 provides examples of rooms that are not considered meeting rooms, such as auditoriums, school rooms and coffee shops.
The parent text in 210.71(B) clearly states that the designer or building owner can locate the receptacle outlets as needed. Sections 210.71(B)(1) for receptacle outlets in fixed walls and 210.71(B)(2) for floor receptacles are only used to determine the total number of required receptacles. As you pointed out, the text in 210.71(B)(1) needs to be revised for clarity.
Multimedia projector overhead
I have noticed that some multimedia projectors have a receptacle outlet provided below the ceiling to plug it in while others plug in above the ceiling. Where the ceiling is not a 300.22(C) space, is it permissible to plug in the projector to a receptacle outlet above the ceiling?
No, the attachment cord for plugging in a multimedia projector is a “power supply cord,” which is a flexible cord and under the scope of Article 400. See the informational note that follows the article scope in Section 400.1 that clarifies sections 400.10 and 400.12 apply to power supply cords.
Section 400.12 lists uses not permitted for flexible cords and flexible cables. List item 400.12(2) prohibits installation of flexible cords and cables through holes in walls, structural ceilings, suspended ceilings, dropped ceilings or floors. The classification of the space above the ceiling determines permitted wiring methods/materials and equipment. It does not play into the determination of flexible cords/cables through holes in suspended or dropped ceilings.
GFCI devices for portable use?
There are requirements in Article 590 that reference GFCI protection that is identified for portable use. This references cord sets and devices. What does “identified for portable use” mean?
The GFCI requirements that you are referring to are located in second-level subdivisions: 590.6(A)(1) for devices permitted in addition to GFCI protected receptacle outlets and 590.6(A)(3), which permits GFCI devices identified as portable to provide protection on older portable generators. These devices must be listed cord sets or devices that incorporate listed GFCI protection for personnel, and they must be identified for portable use, which means they are marked as such.
A standard GFCI receptacle is not identified for portable use. A listed GFCI cord set or device that is identified for portable use provides open neutral protection. A standard GFCI needs line voltage at 120 volts to sense current flow to ground and open. This means that when a standard GFCI loses the neutral connection to the device, it loses the ability to sense a fault, and it will allow current flow to ground without opening. A listed GFCI cord set or device that is identified for portable use will open immediately upon the loss of a neutral connection, providing open neutral protection.
The NEC requires the same level of GFCI protection in carnivals, circuses, fairs and similar events for all receptacles supplied by portable cords. See first-level subdivision 525.23(D).